What causes this clock madness?

Factual Questions
1

So I’m sitting in chemistry class the other day, bored out of my mind. I recently transfered from IB level chem (AKA, the Chemistry Class chosen by nine out of ten over-achieving masochists) to A level chem (AKA the Chemistry Class of the somewhat dull-witted masses). I have lots of time to watch the clock.

And thus, I started thinking. When there’s a power outage at school (disturbingly frequently, maybe monthly or so), the clocks all go crazy. Periodically, the maintainance staff goes around and resets them all, but until then, they’re all wrong. None of them say the same time. Room A may read 5:24, room B may say 2:08, room C, 1:00, and so on. No coherency to the lack of accuracy.

Why does this happen? If they all get shut off and turned on at the same time, why do they get all funky like this?

2

Are they analogue or digital?

Possibilities:

They have a batttery in each that lasts for varying lengths of time after power failure?

They are digital, store the time in volatile memory, and don’t have a zero-on-repower, so when they are turned on the memory settles into sme random time?

3

Your school probably has a Master/Slave clock system, in which a single control panel is used to set the time of all the clocks in the building. I went to a school with such a system back in the early 70’s, and when the power went out and then back on, whatever network protocol they had (eg gears and cables :wink: ) would send spurious signals to all the clocks in the building. Sometimes the hands just whizzed around. When that happened, they needed to be reset manually.